Physical Review Letters
Saturated Optical Absorption by Slow Molecules in Hollow-Core Photonic Band-Gap Fibers
Jan Hald, Jan Conrad Petersen, J. O. Henningsen
Abstract
We report on saturated absorption in a hollow-core photonic band-gap fiber filled with 12C2H2 molecules. We find that slow molecules provide a major contribution to the signal in the limit of low optical power and low pressure where the signal deviates significantly from the usual Lorentzian line shape. In particular, we observe a linewidth reduction of about 3 times as compared to the transit-time limited linewidth.